Synthetic Nanosheets of Natural van der Waals Heterostructures

Abstract

Creation of new van der Waals heterostructures by stacking different two dimensional (2D) crystals on top of each other in ac hosen sequence is the next challenge after the discovery of graphene,m ono/few layer of h-BN,a nd transition-metal dichalcogenides.H owever,c hemical syntheses of van der Waals heterostructures are rarer than the physical preparation techniques.H erein, we demonstrate the kinetic stabilization of 2D ultrathin heterostructure (ca. 1.13-2.35 nm thick) nanosheets of layered intergrowth SnBi 2 Te 4 ,S nBi 4 Te 7 , and SnBi 6 Te 10 ,whichbelong to the Sn m Bi 2n Te 3n+m homologous series,b yasimple solution based synthesis.F ew-layer nanosheets exhibit ultralow lattice thermal conductivity (k lat )of0.3-0.5 Wm À1 K À1 and semiconducting electron-transport properties with high carrier mobility.

n-Type Ultrathin Few-Layer Nanosheets of Bi-Doped SnSe: Synthesis and Thermoelectric Properties

“…17 The presence of Bi 4f 7/2 and Bi 4f 5/2 peaks at 159.6 and 164.95 eV can be attributed to Bi (III) states in Bidoped SnSe sample. 14 In situ chlorination of as-synthesized SnSe and Sn 0.94 Bi 0.06 Se nanosheets was further confirmed from the XPS peak at 198.7 eV (Figure 1e). 17 The actual elemental compositions of SnSe nanosheet samples were obtained further from inductively coupled plasma atomic emission spectroscopy (ICP-AES) and energy-dispersive analysis of X-rays (EDAX).…”

“…The Sn 3d spin−orbit doublet peaks appeared at 488.4 and 496.7 eV with splitting of 8.3 eV (Figure 1e), which can be assigned to Sn 3d 5/2 and Sn 3d 3/2 , respectively. 14 We could be able to deconvolute the broad peak of selenium as Se 3d 5/2 and Se 3d 3/2 at 53.1 and 55.45 eV, respectively. 17 The presence of Bi 4f 7/2 and Bi 4f 5/2 peaks at 159.6 and 164.95 eV can be attributed to Bi (III) states in Bidoped SnSe sample.…”

Ultrathin Free-Standing Nanosheets of Bi2O2Se: Room Temperature Ferroelectricity in Self-Assembled Charged Layered Heterostructure

“…have been successfully synthesized in their ultrathin form. − The discovery of new 2D materials in their ultrathin geometry is, in fact, one of the major thrust areas to mitigate the various impediments with the current candidate 2D materials. Recently, vdW heterostructures, either the assembly of different atomically thin 2D materials forming a new heterostructure , or the synthesis of naturally occurring layered heterostructure materials in their ultrathin form, , have gained wide attention as they offer manipulation of a wide range of functionalities. Recently, the layered oxy-chalcogenide material Bi 2 O 2 Se has emerged as a compelling 2D material for its extremely high carrier mobility (>20,000 cm 2 V –1 s –1 at 2 K) with very low effective mass (0.14 m 0 ), and indirect size tunable band gap (bulk band gap ∼0.8 eV), , which is excellent for electronic and optoelectronic applications − and air stability.…”

Quaternary Chalcogenide-Based Misfit Nanotubes LnS(Se)-TaS(Se)2 (Ln = La, Ce, Nd, and Ho): Synthesis and Atomic Structural Studies

“…Layered-based nanostructures are interesting due to intrinsic structural directionality owing to dissimilar interlayer and intralayer interactions. 6,7 Nanotubes of chalcogenide [8][9][10][11][12][13] and more recently oxide-based 14,15 misfit layered compounds were synthesized in recent years and their structures were elucidated in some detail. The MLC nanotubes are grown by chemical vapor transport (CVT) process along a very significant temperature gradient of about 600 ᵒC.…”